[Histonet] Shrinkage of frozen fixed brain tissue mounted on slides

[CM Bush]

Dear Histonet,
 
I have been cutting frozen fixed human brain tissue, using a freezing stage on a rotary microtome.  The tissue has been very well fixed in 10%NBF, and cryoprotected with sucrose.
 
I cut the sections at 50 um, floated the sections in PBS, mounted them on slides, and allowed them to dry for 48hrs and then Nissl stained.
 
Everything looks nice except that the sections have shrunk down to 20um as measured using a stereology set up. This is very sad.  
 
I guess we will just have to cut thicker sections... 
 
My question is, does this sound like the amount of shrinkage to expect with frozen fixed brain tissue mounted onto slides?  It makes sense that there would be some change due to expansion of freezing water, and then drying on the slide but greater than 50% change?
 
Thank you in advance, for your help.
 
CM Bush